For the past year, I have been using a Hackintosh Core i7 4770K, 16GB Ram (1866 Mhz), 120GB SSD, Nvidia GTX 770 2GB It performs well. No lag. Yosemite running smooth. Running all of the kexts, etc to make most everything work. (iMessage not working... too much of a hassle to get it working.) Anyway, I recently came into a 2009 Mac Pro that has been flashed to 5,1. It has a Westmere 6 Core Xeon @2.93 GHz. It has 8GB RAM installed (4x2GB 1066Mhz). I pulled the GTX 770 from my Hack and installed it into the Mac Pro. Installed a fresh copy of Yosemite onto a Sandisk SSD. I notice that this Mac Pro is a lot laggier than the Hack. Transitions and animations moving between spaces and Mission Control... stuttering. I know that this is a 6 year old machine here... but I am wondering if the processor/chipset is just THAT outdated. Or is the RAM the bottleneck? Would moving from the 1066Mhz to 1333Mhz RAM make that much of a difference? Is it just the fact that it is running 8GB and not the 16GB that the Hack has the difference? The real reason I'd like to fully transition to this Mac is because... it is a REAL Mac and everything will work. I have plans for this Mac... 12 Core upgrade, more RAM, Bluetooth 4.0 upgrade for handoff. Which will give me the most noticeable performance upgrade to curb the lag? EDIT: Also, I am using a Samsung 4K Monitor... maybe that is too many pixels for this setup?